This invention relates to T-nuts for attaching a work bed to a milling or grinding machine. More particularly, it deals with a T-nut to overcome burrs commonly found in the T-slots of the base to which the bed is attached.
Virtually all milling or grinding machines have a base with a T-slot like that shown in this application's FIG. 3. T-nuts are inserted into the slots, from the underside of the base. Their flat heads are retained within an underside of the slot, while their shanks extend upwardly and are exposed.
The shanks typically, like the present invention, have a vertical throughbore that is internally threaded. This permits a work bed to be fastened onto the machine's base, by screwing a bolt through the bed and into the shank's throughbore.
The work bed is required when a machinist wants to mill or grind a part. It holds the piece being machined in place, and is usually a jig, fixture or simple clamp. If the bed is not bolted properly, the finished piece may be machined improperly.
Oftentimes, the T-slots have burrs on their shoulders because of initial tooling. Because the burrs are located under the base, they are often not seen or thought of. Therefore, they are not filed down by the manufacturer.
If the flat head of the T-nut meets a burr during tightening, the head and shank can be tilted slightly. This can throw the attached work bed slightly off kilter and affect the quality of the finished machined part. Since many machined products require extremely close tolerances, this skewing cannot be tolerated.
Accordingly, it is the primary object of the present invention to provide a T-nut which overcomes the burring problem found in T-slots.
It is more specific object to provide a T-nut with a pair of furrows on opposite sides of its base, adjacent to the shank, whereby the furrows straddle any burrs on the T-slot's shoulders and provide a flush or squared sitting of the nut in the slot.
It is another object to provide such a T-nut, which is made from a cold-drawn process, whereby the nut is simple to manufacture, yet extremely durable to use.
The above and other objects of this invention will become more readily apparent when the following description is read in conjunction with the accompanying drawings.